1. Field of the Invention
The present invention relates to a battery for an electric vehicle. More particularly, to the structure of the connection including wiring for monitoring voltage connected to the battery when the battery is arranged in the electric vehicle provided with a swing arm. In addition, the present invention relates to a control circuit for an electric vehicle. More particularly, to a structure for radiating heat in the control circuit that controls the energizing of an electric motor that drives the electric vehicle.
2. Description of Background Art
A structure for fixing a battery in an electric vehicle such as an electric motorcycle, a fuel cell motorcycle and a hybrid motorcycle is disclosed, for example, in JP-A No. 2008-221976. The structure includes one end of a swing arm coupled to a swinging shaft with the other end of the swing arm supports a rear wheel. An electric motor for driving the rear wheel is installed on the side of the other end of the swing arm and the battery is arranged in a position in the vicinity of the swinging shaft of the swing arm is disclosed.
In JP-A No. 2006-182315, a configuration wherein a battery is arranged on the front side in a vehicle body is disclosed. A control unit for controlling a motor as a driving source is arranged on the rear side in the vehicle body. Both are connected via a harness.
Further, in JP-A NO. 2005-108693, a battery module is disclosed in which a plurality of battery cells are connected in series. A predetermined voltage is acquired. A method of configuring the battery module by laminating the plurality of battery cells each of which is housed in a predetermined case after each battery cell is wrapped in a soft flexible laminated film and is sealed to be a plate-like laminated cell.
In JP-A No. 2008-221976, though it is described that the battery is arranged in the position in the vicinity of the swinging shaft of the swing arm, the electric connection between the battery and the control unit for controlling the motor is not concretely disclosed. It is possible to improve the electrically connecting structure when the battery is arranged in the swung swing arm.
In the case of the configuration disclosed in JP-A No. 2006-182315, as a location of the battery and a location of the control unit are apart, JP-A No. 2006-182315 has a problem in that the harness that connects both is long with the possibility of an effect on noise.
In the electric vehicle, when motor control is executed, it is an important element to grasp a state of the battery which has a large effect on motor control by the control unit.
However, in the configuration wherein the battery is housed in the swing arm as in the technique described in JP-A No. 2008-221976, a secured housing space is limited. Further, as the space occupied by the case described in JP-A NO. 2005-108693 is also required in the battery cell wrapped in the case and JP-A NO. 2005-108693 has a problem in that it is difficult to increase the capacity of the battery.
As a method for surmounting these problems, it is conceivable that “a potting process” in which a laminated cell is fixed by injecting potting material into a circumference of the laminated cell after a plurality of laminated cells are directly housed in a housing space encircled by external walls of a swing arm and thereafter hardening the potting material. However, it is difficult to inject liquid potting material into only locations required for fixing a battery and when the potting material is also injected into a location not required, the weight of the swing arm is increased and a flow of gas emitted from each laminated cell may be prevented.
A structure for radiating heat generated in an electronic component, a structure for touching a heating element to a lid of a control box via a heat-conduction sheet in the control box in which electronic components are housed and for radiating heat in an electric hybrid bicycle for example is described in JP-A No. 2005-174994.
In JP-A No. 2006-66895, a structure for a power module of an electric cart is configured by a plurality of layers wherein an element is arranged on each layer and the elements are connected via a metallic plate.
In JP-A No. 2005-174994, the configuration wherein the element is touched to the lid that radiates heat via the heat-conduction sheet is described. However, when a plurality of elements are provided, the heat radiation of the whole structure provided with each element is required to be considered.
In JP-A No. 2006-66895, the structure wherein the plural elements are connected to the laminated plate (the metallic plate) is described. However, as the heating element is mounted on every metallic plate and the heating elements are laminated, the whole structure is a large-size. In addition, as the heating elements are connected to the same metallic plate and a phenomenon wherein heat is confined in a package occurs, the JP-A No. 2006-66895 has a problem wherein sufficient heat radiation is not performed when heat radiation is considered in a single package.